Cable Lug Comprising a Nut or Functional Part, Method for the Production of Such a Cable Lug, and Nut

ABSTRACT

The invention relates to a cable lug ( 1 ) comprising a receiving tube section ( 4 ) for the cable ( 19 ), a flat piece-connecting section ( 5 ) that is molded on and is provided with a bore ( 6 ), and a nut ( 2 ) which is captively mounted on the flat piece-connecting section ( 5 ) and is preferably rotatably mounted. Said nut ( 2 ) does not penetrate the flat piece-connecting section ( 5 ) while being mounted by means of a shaped mounting material section ( 16 ) of the flat piece-connecting section ( 5 ), which extends into an undercut ( 9 ) that is embodied on the nut. In order to be able to rotatably mount the nut or the functional part, the mounting material section ( 16 ) is accommodated in the undercut ( 9 ) with an axial clearance. Furthermore, the mounting material section ( 16 ) is rooted in an area of the flat piece-connecting section which is lowered in a step-type manner. Said lowered area is rotationally symmetrical and is provided with a conical section which opens outward and vertically and encompasses at least one conical area. The invention also relates to a method for compression-connecting a functional part such as a nut to a cable lug as well as a nut that is suitable for this purpose.

In first instance, the invention relates to a cable lug with a tubularreceiving portion for the cable, an integrally formed flat partconnecting portion which has a hole, and a nut which is held captively,preferably held to be rotatable, on the flat part connecting portion,the nut not passing through the flat part connecting portion and beingheld by a reshaped holding material portion of the flat part connectingportion which projects into an undercut formed on said nut.

The invention also relates to a cable lug with a tubular receivingportion for the cable, an integrally formed flat part connecting portionwhich has a hole, and a functional part which is held captively,preferably held to be rotatable, on the flat part connecting portion,the functional part being held by a holding material portion whichprojects into an undercut formed on said functional part, this holdingmaterial portion being rooted in a region sunk-in in a step-like mannerwith respect to the unaffected surrounding region of the flat partconnecting portion, the undercut being formed with an axial extent whichis equal to or less than the axial extent (thickness) of the unaffectedflat part connecting portion.

Various configurations of cable lugs of this type are already known.Reference is to be made, for example, to DE 10310164 A1.

In terms of the prior art, reference is also to be made to EP 667 936B2, and furthermore also to U.S. Pat. No. 5,256,019.

The invention also relates to a method for forming a connection, whichis captive but allows axial and possibly rotary movement, of a cable lugto a functional part, such as a nut, the cable lug having a tubularreceiving portion for the cable and a flat part connecting portion, andthe functional part being pressed into the undeformed flat partconnecting portion by penetrating or passing through a hole which isformed therein.

In this respect, reference is also to be made to the prior art alreadymentioned above. In the method known from U.S. Pat. No. 5,256,019, astep-like area is formed in the course of the pressing-in process, thisstep-like area having two surfaces which run perpendicular to oneanother, respectively horizontally and vertically. Although this resultsin the formation of the desired holding material portion, the entiredeformed portion enters the region of the flat part connecting portionof the cable lug which is positioned vertically beneath the associatedstepped area of the screw or of the functional part.

Finally, the invention relates to a nut, preferably for forming apress-connection with a flat part connecting portion of a cable lug, oneend of the nut, in relation to its tightening or loosening direction,having a radially opening undercut which is provided in the axialdirection of the nut and has an upper and a lower delimiting surface.

In terms of the prior art, reference is to be made to U.S. Pat. No.3,253,631, DE 558873 and DE 9412215 U1 in this respect.

In the case of the known cable lugs mentioned in the introduction, theholding material portion is in each case accommodated in the undercut ofthe nut or the functional part such that said undercut is filled, or theundercut is formed to be very large in the axial direction and formed inone direction by the start of the thread (U.S. Pat. No. 5,256,019). Anovel design is sought here, in particular with regard to rotatableretention of the nut or the functional part.

On the basis of the known method, it is also the object of the inventionto provide an advantageous method for press-connection of a functionalpart, such as a nut, to a cable lug.

Last but not least, it is an object of the invention to provide a nutwhich can be used advantageously in an item comprising a combination ofcable lug and functional part, such as a nut, or when carrying out amethod for forming a connection between a functional part, such as anut, and the cable lug.

With regard to a cable lug with a nut held therein, the object isachieved on the basis of the above-described state of the art in that itis provided that the holding material portion is accommodated in theundercut with an axial clearance. A radial play may also be possiblyprovided. Firstly, this is advantageous with respect to thermal loadingof the connection. As a result of the holding material portion findingspace to move in the undercut, certain changes in volume, which areattributable, for example, to different material expansions when heated,can advantageously be accommodated. However, the design solution isitself also inherently directly suited to realizing a rotatable mountingof the nut. Secondly, the inventive concept can, in principle, also beimplemented by rotatability being prevented in a positively lockingmanner, for example by rotation-prevention projections which extendvertically in the seat region of the nut and can be overcome by beinglifted.

If a functional part in generic terms is provided, the object isachieved with a cable lug in which provision is in particular made forthe step-like sunk-in region to be rotationally symmetrical and have aconical portion which is open outward and upward and has at least oneconical surface. The combination of the rotationally symmetrical formwith the outwardly and upwardly open conical portion functionseffectively against possible undesired jamming of the functional part inthe cable lug. Undesired jamming does not at the same time mean alsothat prevention of rotation cannot nevertheless still be present.

In terms of the method, the invention provides for a rotationallysymmetrical circumferential step-like area to be formed in the flat partconnecting portion in the course of the pressing-in process, at leastone of the step surfaces being formed as a conical surface running at anacute angle to a horizontal or a vertical. As a result of the stepsurfaces running in the configuration mentioned, the perpendicular stepsurface or the step surface which, according to the invention, opensobliquely outward is substantially realized by the deformation. Acertain elastic reverse deformation is correspondingly producedfollowing conclusion of the pressing-in process, this elastic reversedeformation tending to lift the functional part. On account of theprofiles mentioned of the stepped area, the functional part can bepositioned largely free from the step surfaces, and this isadvantageously beneficial for the rotatability of the functional partwhich may possibly be desired.

In terms of the nut, the object is achieved with an item in which it issubstantially provided that the undercut is formed to be rotationallysymmetrical and the upper delimiting surface is part of a rotationallysymmetrical stepped area which is formed on the nut. The upperdelimiting surface of the undercut runs directly into said stepped area,which finally always opens upward and outward.

The features of the further claims are explained below substantially inthe form of subclaims, however they may also each be important in theirown right.

Thus it is advantageous if the step surface which runs at an acute angleto the perpendicular once again runs into a horizontal surface. Thishorizontal surface is accordingly disposed radially outside said stepsurface.

It is also preferred for the undercut which is formed on the nut or thefunctional part to be formed in a region which—at least in relation tothe nut—does not have an associated (internal) thread.

The holding material portion is preferably rooted in a portion of theflat part connecting portion which has been sunk-in in a step-likemanner with respect to a surrounding region of the flat part connectingportion.

In particular, it is also preferred for said step surfaces to be planar,independently of their oblique orientation relative to a horizontal orvertical.

In terms of the undercut, it is also preferred for the lower delimitingsurface of the undercut to extend in a vertical projection over morethan half of the associated stepped area in the radial direction, saidstepped area being formed at the lower end of the associated actual nutpart or head of the functional part. This undercut is also preferablyformed independently of the thread and so as not to (radially) overlap athread of the nut. The inner face of the undercut region is formed to becylindrical in the case of the nut. The relevant cylindrical surfacepreferably merges into the root of the internal thread which is formedin the nut. In the axial direction, the undercut preferably extends overa quarter or more of the thickness of the flat part connecting portion.

From the point of view of the method and installation, a procedure iscarried out such that the hole in the flat part connecting portion ofthe cable lug is large enough for the neck of the nut, which neck asnoted projects downward and has the undercut, to be easily inserted intothe hole. A pressing force is then applied to the nut from above, thispressing force causing said stepped area to be sunk into the material ofthe flat portion of the cable lug while at the same time bulging out theholding material portion which is formed from the material of the flatpart of the cable lug. After the nut is relieved of said pressing force,the nut is captively secured to the cable lug, the nut being at the sametime freely rotatable.

The angle—which results in a conical surface—of the rising portion ofthe stepped area is preferably an acute angle, more preferably in therange of 1 to 60 degrees, still more preferably in the region of 45degrees. However, the disclosure also includes all relevant intermediatevalues, for example 2, 3 degrees or 46, 47 degrees etc.

If the stepped area has a step surface which is oriented on a horizontaland a step surface also runs at an angle to the horizontal, this angleis preferably also an acute angle, more preferably in the angular rangesspecified above in relation to the rising portion of the stepped area,and to be precise, the angle can in this case be formed such that itcounts both positively and negatively. It is further preferred here forthe angle of the step surface which is oriented to the horizontal toalways be selected to be smaller (in terms of magnitude) than that ofthe step surface which is oriented to the vertical.

In first instance, the nut with said shaped portions can be produced asa turned part. However it may also be produced, for example, as anextruded part, said neck portion being integrally formed at the bottominitially in the form of a cylindrical tube, and then in a second stepbeing upset such that the required and described undercut is produced.

The cable lug is preferably one which is formed from a solid material,the flat portion then being pressed by reshaping.

Said connection between the nut, which is generally composed of a steelmaterial, or another functional part, and the flat portion of the cablelug is also assisted by the cable lug usually consisting of acomparatively soft material, specifically copper or aluminum.

On account of the described configuration of the functional part,pressing-in produces a characteristic compression curve, in firstinstance specifically with force rising in a comparatively linear manneralong the path and then angling off in a second portion of thecompression curve in which the force rises more sharply as plotted overthe path. This characteristic allows compression to be controlled in anadvantageous manner in relation to the pressing force applied. It ispossible to prespecify a typical pressing force which is located to asufficient extent in the steep region of the curve, and be sure thatmounting of the functional part on the cable lug appropriately for itsfunction is achieved in each case when this pressing force is reached.

It is also preferred for the hole in the cable lug to be formed with ahole step. The hole step is preferably already provided before thedeformation. This is advantageous in respect of connection to a pin onwhich, in one application, the cable lug is for example to be fitted.This pin, which has a thread at its head end, has a radial projectionbelow the thread. The cable lug outside the hole sits on this area. Inorder to be able to utilize this projection as advantageously aspossible in terms of area, it is recommended to make the hole narrowerin the lower region which faces the pin, that is to say to provide itwith the said hole step.

In terms of the functional part, in particular the nut, it is alsopreferred for the horizontal surface to have a circular outer contour.For a conventional nut with a polygonal contour, that is to say forexample a hexagonal contour, this can be achieved, for example, byintegrally forming a flange, at the lower end, on the head of thefunctional part, that is to say on the polygonal section of the nut inthis case. The top end of this flange has a fitting area which canadvantageously be used by a corresponding pressure-exerting tool. As aresult of the outer contour being round, the desired rotatability of thenut cannot be prevented, for example by a hexagonal depression due tosaid nut being pressed into the surface of the flat part connectingportion of the cable lug.

In addition to the nut which has already been mentioned, the functionalpart in question may also be a screw. Furthermore, it may also be forexample a sleeve or a mandrel.

The invention is explained in greater detail below with reference to theaccompanying drawing which illustrates only exemplary embodiments, andin which

FIG. 1 shows a cable lug with a nut which is associated with the flatpart, before pressing;

FIG. 2 shows the item according to FIG. 1, sectioned in the region ofthe flat part;

FIG. 2 a shows an enlargement according to the detail IIa from FIG. 2;

FIG. 3 shows the item according to FIG. 1 in position fitted onto thecable lug;

FIG. 4 shows a cross-sectional illustration, which corresponds to FIG.2, of the item according to FIG. 3;

FIG. 5 shows the item according to FIG. 1 and FIG. 3 in a pressedposition;

FIG. 6 shows a sectional illustration, which corresponds to FIG. 2 andFIG. 4, of the item according to FIG. 5;

FIG. 6 a shows an enlargement according to the detail VIa from FIG. 6;

FIG. 7 shows an illustration with a nut screwed onto a threadedconnecting pin;

FIG. 8 shows an illustration of a functional part in the form of ascrew;

FIG. 9 shows the item according to FIG. 8 with a screw seated on theflat part of the cable lug, before pressing;

FIG. 10 shows an alternative embodiment of a nut which is connected to acable lug, in perspective view;

FIG. 11 shows a cross-section through the item according to FIG. 10 inthe region of the flat part connecting portion;

FIG. 11 a shows an enlargement according to portion XIa from FIG. 11;

FIG. 12 shows a cross-section through FIG. 11 in the pressed-in state ofthe nut;

FIG. 13 shows a perspective view of a further embodiment of thefunctional part in the form of a nut fitted onto the cable lug;

FIG. 14 shows a cross-section through the item according to FIG. 13,before the pressing;

FIG. 15 shows an enlargement of the region XV in FIG. 14;

FIG. 16 shows an illustration according to FIG. 13, following pressing;

FIG. 17 shows a cross-section through the item of FIG. 16; and

FIG. 18 shows an enlargement of the region XVIII in FIG. 17.

A cable lug 1 with a functional part 3, which is in the form of a nut 2in this case, is presented and described, in first instance withreference to FIGS. 1 to 7.

For a connection between the nut 2 and the cable lug 1 which is secureagainst coming free, that is to say in a manner secured against becomingdetached, but such that the connection is rotatable, the nut 2 ispressed to the cable lug 1, as is shown by FIGS. 5 to 6 in particular.

Specifically, the cable lug 1 has a tubular receiving portion 4 and aflat part connecting portion 5. The cable 19 is introduced into thetubular portion 4 and then held therein, for example by a press fit, theintention being for electrically reliable connection to be achieved bymeans of the cable lug 1.

The cable lug 1, which is formed from a solid material in the exemplaryembodiment, also has a hole 6 in the already mentioned press-deformedflat part connecting portion 5. In the exemplary embodiment, the nut 2is inserted into this hole 6 and then connected to the cable lug 1, thatis to say specifically to the flat part connecting portion 5, in acaptive but rotatable manner, by being pressed down in the manner stillto be described.

As can be seen in further detail from the illustrations of FIGS. 2, 4and 6, the nut 2 has an internal thread 7, in the exemplary embodimentwith an upper plastic insert 8 in order to prevent the nut 2 frombecoming detached. In this respect, there is in question a self-lockingnut.

An undercut 9 is integrally formed on the nut 2, at the lower end. Inthe exemplary embodiment, this undercut 9 is produced by turning on alathe.

The undercut 9 begins below the lower end of the internal thread 7. Onthe inner side, the undercut 9 has a cylindrical surface 10 which isaxially flush with the root of the internal thread 7.

Specifically, the undercut 9 is formed by a lower delimiting surface 11and an upper delimiting surface 12. The upper delimiting surface 12 isalso part of a stepped area which is formed on the nut 2, at the lowerend.

The stepped area of the nut 2, which is illustrated in detail on anenlarged scale in the magnified illustration, is as it were the negativeof the stepped area which is positively formed in the flat partconnecting portion 5, in the pressed state.

More specifically, the stepped area comprises a vertical surface 13 andthe delimiting surface 12 which has already been discussed. In theexemplary embodiments described here, the two surfaces, the delimitingsurface 12 and the vertical surface 13, extend at an acute angle α and βrespectively in relation to a horizontal H and a vertical Vrespectively. The acute angle α or β is preferably in the range of 1 to60°, more preferably between 10° and 30° for α, and between 20° and 50°for β. In the exemplary embodiment, the angle α is 15° and the angle βis 30°.

The vertical surface 13 merges in a radially outward direction into ahorizontal surface 14 which, however, is formed with a varying radialextent over the circumference on account of the hexagonal form of thenut 2 in the exemplary embodiment.

This varying radial extent of the horizontal surface 14 can be seen inthe illustration according to FIG. 3, in which the nut 2 is illustratedin a position fitted onto the flat part connecting portion 5 beforepressing. In this case, the hole 6 extends partly, still radially,beyond an associated vertical flat surface 15 of the nut 2.

FIG. 4 illustrates a cross-section through FIG. 3, likewisecorrespondingly in the state before pressing.

In contrast, FIGS. 5 and 6 illustrate the state following pressing.

It is pertinent that a holding material portion 16 is formed from theflat part connecting portion 5, said holding material portion extendinginto the undercut 9 of the nut 2. The holding material portion 16 ispart of the stepped area which has already been mentioned and ispositively formed in the flat part 5 but, in the same way, has theoblique orientation with respect to a horizontal H or vertical V, asalready described. In this case, the holding material portion 16 clearlyextends radially inward beyond the hole 6 of original diameter whichremains in the lower region, seen over the thickness of the holdingmaterial portion 16.

The step-like sunk-in region with the step surfaces 17 and 18 which iscreated in the holding material portion 16 following pressing is formedsuch that it is rotationally symmetrical over the circumference of thehole 6. That is to say, the area is produced in a notional sense byrotation of a template. There are no undercuts in the area in relationto the direction of rotation of the notional template mentioned (this isnaturally an example of shaping as it is used as required in castingmolds; this is only mentioned here in order to make clear the nature ofthe rotationally symmetrical area).

As can be seen, the holding material portion 16 is held in the undercut9 both with axial and radial play. However, this play is comparativelysmall, as can be gathered, in terms of magnitude in the region of thethread depth of the internal thread 7 of the nut 2, that is to say inthe millimeter range or in the range of tenths of a millimeter.

The holding material portion 16 itself is also formed to be rotationallysymmetrical. The undercut 9 completely laterally overlaps the holdingmaterial portion 16 in the pressed state.

In FIG. 7, there is illustrated the connection state of the cable lug 1,with the pressed-in cable 19 located therein, to an (electrical)connection part 20. The connection part 20 has a screw pin 21 by meansof which the nut 2, which is captively but rotatably press-connected tothe cable lug 1, is screwed on. In this way, a desired pressure/buttingconnection is produced between the lower side of the flat partconnecting portion 5 and the upper side of the connection part 20.

The embodiment of FIGS. 8 and 9 shows a functional part 3 in the form ofpin 22. Said pin may possibly also be a screw on which a thread can alsobe formed at the lower end of the undercut 9.

Substantially the same conditions are produced as for the nut 2described in relation to FIGS. 1 to 7, only now the pin 22 of thefunctional part 3 passes through the hole 6. For pressing purposes, acounter holder which has a corresponding receptacle or hole 6 for thepin 22 is suitably used here.

It can be gathered with reference to FIGS. 10 and 11, in particular incomparison with FIG. 3 for example, that the nut 2 has an upper shapedportion 23 with an annularly circumferential planar pressing area 24.The required compressive force can be applied to the nut 2 by means ofthis pressing area 24 using a suitable pressure-exerting tool, in orderto form the holding material portion 16 out of the flat part connectingportion 5 of the cable lug 1 in the course of the pressing. The nut ismerely pushed into the flat part connecting portion 5 from above, as hasalso already been described previously. The pressing area 24 issubstantially smaller than the projected full surface of the nut 2. Itcorresponds at least to less than half of this projected completesurface.

The already mentioned plastic part 8 is accommodated within thestructure 23, said plastic part being aligned, in a manner correspondingto a self-locking nut and as can also be seen from the cross-sectionalillustration according to FIG. 11, with the internal thread line of thescrew thread 2 on an inner wall, which wall has a cylindrical shape.

It is also material to the embodiment of FIG. 11, as can also be seenfrom the detailed illustration of FIG. 11 a, that the angle α is chosento be 0° whereas the angle β is chosen to be 45° in this case.

Furthermore, it is pertinent that, as shown in FIG. 12, the horizontalsurface 14 does not rest on the flat part connecting portion 5 in thecompressed state. Instead, it hovers as it were over the flat partconnecting portion when the pressing-in is correct. In other words, thepressing force is selected such that, with the given configuration ofthe stepped area, a pressing-in process is performed only to the extentthat the surface 14 does not come to rest on the flat part connectingportion 5, and preferably also without taking into account the elasticrecovery which results after the nut is relieved of the pressing force,that is to say in such a way that the surface 14 does not come intocontact with the upper surface of the flat part connecting portion 5 atany time in the pressing process.

In first instance, it is pertinent to the embodiment of FIGS. 13 to 18that the hole (6) is stepped in the axial direction. Starting from arelatively large diameter at the top, which is associated with thefunctional part, specifically with the nut 3, the diameter of the holechanges to a smaller diameter toward the bottom by way of a hole step25. The hole step 25 is formed symmetrically with respect to the centerof a longitudinal axis of the hole.

The hole step 25 serves to increase the area on the lower end of theflat part connecting portion in the vicinity of the hole 6, thisbecause, in one application, the flat part connecting portion, togetherwith the nut 3, is fitted and screwed onto a stepped pin which has athread at its upper end. The flat part connecting portion accordinglyhas to sit on a relatively narrow, annularly circumferential area of thepin. This seating and therefore contact area can advantageously beincreased in size by the described hole step 25.

In terms of production, the procedure followed may be, for example, thatthe upper portion of the hole 6 is pressed in and then, in a secondworking step, the lower region of the hole is cut or punched out,leaving the hole step 25. Accordingly, a cut edge can be established inthe cable lug in the lower region of the hole and, in contrast, plasticdeformation in the upper region.

A radial extent r, compare FIG. 15, of the hole step 25 preferablycorresponds to the radial depth T, compare FIG. 11 a for example, of theundercut 9. Furthermore, said radial depth T of the undercut 9 can alsocorrespond to the vertical height of the vertical surface or the steppedarea 13, 17 in this case.

It is also important in the embodiment described here that, in the caseof the illustrated nut 3, a circumferential compression flange 26 isintegrally formed at the lower end of the nut. This compression flange26 extends from the lower horizontal surface 14 over a height whichcorresponds to approximately one third of the vertical height of thehead of the functional part, here the nut 3, this height being measuredfrom the horizontal surface 14 up to the pressing area 24.

If a horizontal flange 26, as described here, is provided for thefunctional part or the nut, the pressing area 24 is no longer of primaryimportance. Said pressing area may also be dispensed with or formed inthe manner illustrated in FIGS. 1 to 7 for example.

The compression flange 26 serves the purpose of enabling apressure-exerting tool to be fitted. Relatively high compression forcesfor press-connecting the functional part or the nut 3 to the cable lug 1can then be applied by means of this compression flange.

Since this produces a substantially larger lower horizontal surface 14than corresponds to the polygonal contour of the nut 3, this is alsoadvantageous in terms of the described pressing process, which can becontrolled, specifically as a function of force, up until there is asharp rise in the pressing force, which signals engagement of thehorizontal surface 14 on the flat part connecting portion 5 of the cablelug 1.

The radial extent of the compression flange 26 in relation to a flatface of the polygonal portion of the nut 3 corresponds, in the smallestradial extent, to one twentieth to one fifth of the diameter of thescrew 3, as measured in the region of the polygonal portion andcentrally with respect to a flattened portion.

The surface, on which the pressure-exerting tool can sit, of thecompression flange 26 can run downward in a slightly inclined manner,but can also run horizontally.

The vertical height of the hole 6 in the region of the relatively smalldiameter, that is to say below the hole step 25 as seen from above, isselected such that the lower termination of the undercut 9 of thefunctional part does not rest on the step in the pressed state either.In the exemplary embodiment, the screw including the undercut 9 ends, asshown, above the hole step 25 in the pressed state also.

The functional part, specifically the nut 3 of the last-describedembodiment, can also be combined with a hole as is further describedabove. On the other hand, the functional parts as are further describedabove can also be combined with a hole as is explained in relation tothe last-described exemplary embodiment.

All disclosed features are (in themselves) pertinent to the invention.The disclosure content of the associated/accompanying priority documents(copy of the prior application) is also hereby incorporated in itsentirety in the disclosure of the application, including for the purposeof incorporating features of these documents in claims of the presentapplication.

1-28. (canceled)
 29. A cable lug in combination with a nut, comprising:said cable lug having a tubular receiving portion for a cable, anintegrally formed flat part connecting portion connected to said tubularreceiving portion, said flat part connecting portion having a holetherethrough defined by a wall, said hole having a central axis; andsaid nut comprising a body having an undercut, said nut being heldcaptively and rotatable, on the flat part connecting portion, the nutnot passing through the flat part connecting portion and being held by areshaped holding material portion of the flat part connecting portionwhich projects into said undercut, said reshaped holding materialportion being accommodated in the undercut, wherein an axial clearanceis provided between said reshaped holding material and the wall whichdefines said hole.
 30. A cable lug in combination with a functionalpart, comprising: said cable lug having a tubular receiving portion fora cable, an integrally formed flat part connecting portion connected tosaid tubular receiving portion, said flat part connecting portion havinga hole therethrough defined by a wall, said hole having a central axis;and a functional part comprising a body having an undercut, saidfunctional part being held captively and rotatable on the flat partconnecting portion, the functional part being held by a holding materialportion which projects into said undercut, this holding material portionbeing seated in a region sunk-in in a step-like mariner with respect tothe unaffected surrounding region of the flat part connecting portion,the undercut being formed with an axial extent which is equal to or lessthan the axial extent of the unaffected flat part connecting portion,said step-like sunk-in region is rotationally symmetrical and has aconical portion which is open outward and upward and has at least oneconical surface.
 31. The combination according to claim 29 or 30,wherein the holding material portion is accommodated in the undercutwith radial play.
 32. The combination according to claim 29, wherein theholding material portion has a surface which faces the nut or thefunctional part and runs directly into a conical area of the flat partconnecting portion.
 33. The combination according to claim 30, whereinthe conical area rims directly into a surface of the holding materialportion, which surface faces the functional part.
 34. The combinationaccording to either of claims 29 or 30, wherein the holding materialportion is formed to be rotationally symmetrical.
 35. The combinationaccording to claim 30 or 32, wherein the conical area of the conicalportion is formed to be rotationally symmetrical.
 36. The combinationaccording to either of claims 30 or 32, wherein two conical surfaces areprovided, and in that at least one of the conical surfaces of theconical portion runs at an acute angle to a horizontal or a vertical.37. The combination according to claim 29 or 30, wherein the undercut isformed outside a thread of the nut or the functional part.
 38. Thecombination according to claim 29, wherein an inner face of the undercuthas a cylindrical surface.
 39. The combination according to claim 38,wherein the cylindrical surface of the undercut merges into the threadroot of the nut.
 40. The combination according to either of claims 29 or30, wherein both an upper and a lower delimiting surface of the undercutoverlap the flat part connecting portion in a lateral projection. 41.The combination according to claim 40, wherein the lower delimitingsurface of the undercut extends over more than half of the associatedstepped area in a vertical projection.
 42. The combination according toclaim 40, wherein an upper delimiting surface of the undercut is part ofa stepped area.
 43. The combination according to claim 29 or 30, whereinthe hole is formed with a hole step.
 44. The combination according toclaim 43, wherein the hole step is formed in the lower region of thehole which faces away from the nut or functional part.
 45. Thecombination according to claim 43, wherein the hole step projects towardthe interior of the hole.
 46. The combination according to claim 43,wherein a radial extent of the hole step corresponds to a radial depthof the undercut.
 47. The combination according to claim 43, wherein, interms of depth, the hole step is formed outside the lower region of thenut or functional part.
 48. Method for forming a connection comprising:providing a cable lug and a functional part, the cable lug having atubular receiving portion for a cable and a flat part connecting portionconnected thereto, said flat part connecting portion having an aperturedefined by a wall provided therethrough; pressing said nut into saidflat part connecting portion by passing a portion of said nut throughsaid hole such that a rotationally symmetrical circumferential step-likearea comprising at least one step surface is formed in the flat partconnecting portion, wherein at least one of the step surfaces forms aconical surface running at an acute angle to a horizontal or to avertical.
 49. Nut which can be inserted into a hole in a cable lug,comprising: a body having a radially opening undercut which is providedin an axial direction of the nut and has an upper delimiting surface anda lower delimiting surface, said undercut being formed to berotationally symmetrical and the upper delimiting surface is part of arotationally symmetrical stepped area.
 50. Nut according to claim 49,wherein the undercut does not laterally overlap a thread of the nut. 51.Nut according to claim 49, wherein an upper end of said body has apressing area which is smaller than an overall area projected in theaxial direction of said body.
 52. Nut according to claim 51, wherein thepressing area is planar.
 53. Nut according to claim 49, wherein a stepedge of the step area is positioned radially outside the undercut at aspacing which corresponds to a radial extent of the undercut.
 54. Nutaccording to claim 49, further including a plastic insert attached tosaid body.
 55. Nut according to claim 54, wherein the plastic insert ispartly covered by a pressing area.
 56. Nut according to claim 49,wherein the step area merges into a horizontal surface.
 57. Nutaccording to claim 56, wherein the horizontal surface has a circularouter contour.
 58. Nut according to claim 56, wherein a radially outerregion of the horizontal surface is part of a compression flange whichextends radially outwardly from said body.
 59. Nut according to claim58, wherein the undercut is positioned within a vertical projection ofsaid body.
 60. A captive clinch nut for rotatable attachment to anapertured sheet, comprising: a nut body having an axial threaded bore; afirst bearing surface on a bottom side of side of said nut body; adisplacer unitary with said nut body and located directly below saidfirst bearing surface, the displacer having an outside diameter lessthan an outside diameter of said first bearing surface; a rigid tubularshank being substantially non-deformable in its unattached free state,unitary with said nut body, and coaxially extending from said displacer,said shank being outwardly flared toward a distal end; wherein a neck ofsaid shank immediately adjacent said displacer has an outside diameterless than the outside diameter of said displacer and less than anoutside diameter of said flared end; and an undercut between said neckand said displacer for receiving a cold flow of metal of said sheet. 61.The captive clinch nut of claim 60, further including a second displacersurface on a bottom side thereof parallel to said first bearing surface.62. The captive clinch nut of claim 61 further including an outwardlyextending flange forming a base of said nut body.
 63. An assembly ofparts including the captive nut of claim 61 and further including thesheet having the aperture formed therein, the displacer and shank ofsaid nut body being located within said sheet and being coaxial withsaid aperture such that a ductile deformed portion of said sheet lieswithin the undercut; and a space between said shank and an inside wallof said sheet aperture such that the nut is freely rotatable within saidsheet while being secured against substantial axial displacementtherefrom.
 64. An assembly of parts as defined in claim 63, wherein saidthe nut is axially displaceable from said sheet a predetermined amount.65. The assembly of parts of claim 63, wherein the combined lengths ofsaid displacer and said shank are less than the thickness of said sheetsuch that said shank does not extend beyond a back side surface of saidsheet.
 66. The assembly of parts of claim 65 wherein said nut iscomposed of a material having a hardness substantially greater than saidsheet.
 67. The assembly of parts of claim 66 wherein the portion of saidsheet which lies within said undercut area is received therein by thecold flow of metal of said sheet.
 68. The captive clinch nut of claim62, further including a head portion having tool-engaging flats on itsouter surface.
 69. The captive clinch nut of claim 68, wherein said headis of hexagonal cross-section.
 70. The captive clinch nut of claim 69,wherein said threaded bore extends through the entire length of the nut.71. The captive clinch nut of claim 61, wherein the outer surfaces ofsaid displacer and said shank are of reduced friction for providingbearing surfaces of said nut against said sheet.
 72. The captive clinchnut of claim 61, wherein said first bearing surface is integral withsaid nut body.
 73. The captive clinch nut of claim 61, wherein thedisplacer is tapered inwardly.
 74. An assembly of parts including thecaptive nut of claim 61 and further including a sheet having an apertureformed therein, the displacer and shank of said nut body being locatedwithin said sheet and being coaxial with said aperture such that aductile deformed portion of said sheet lies within the undercut; and aspace between outside surfaces of said shank and an inside wall of saidsheet aperture such that the nut is freely rotatable within said sheetwhile being secured against substantial axial displacement therefrom,wherein the combined lengths of said displacer and said shank are lessthan the thickness of said sheet such that said shank does not extendbeyond a back side surface of said sheet.
 75. The assembly of parts ofclaim 74, wherein said nut is composed of a material having a hardnesssubstantially greater than said sheet.
 76. The assembly of parts ofclaim 75, wherein the portion of said sheet which lies within saidundercut area is received therein by the cold flow of metal of saidsheet.
 77. The captive clinch nut of claim 60, further including asecond displacer surface on a bottom side thereof which is not parallelto said first bearing surface.
 78. The captive nut of claim 77, whereinthe displacer is tapered inwardly.
 79. The captive clinch nut of claim60 further including an outwardly extending flange forming a base ofsaid nut body.
 80. An assembly of parts including the captive nut ofclaim 60 and further including the sheet having the aperture formedtherein, the displacer and shank of said nut body being located withinsaid sheet and being coaxial with said aperture such that a ductiledeformed portion of said sheet lies within the undercut; and a spacebetween said shank and an inside wall of said sheet aperture such thatthe nut is freely rotatable within said sheet while being securedagainst substantial axial displacement therefrom.
 81. An assembly ofparts as defined in claim 80, wherein said the nut is axiallydisplaceable from said sheet a predetermined amount.
 82. The assembly ofparts of claim 80, wherein the combined lengths of said displacer andsaid shank are less than the thickness of said sheet such that saidshank does not extend beyond a back side surface of said sheet.
 83. Theassembly of parts of claim 82, wherein said nut is composed of amaterial having a hardness substantially greater than said sheet. 84.The assembly of parts of claim 83, wherein the portion of said sheetwhich lies within said undercut area is received therein by the coldflow of metal of said sheet.
 85. The captive clinch nut of claim 60,further including a head portion having tool-engaging flats on its outersurface.
 86. The captive clinch nut of claim 85, wherein said head is ofhexagonal cross-section.
 87. The captive clinch nut of claim 86, whereinsaid threaded bore extends through the entire length of the nut.
 88. Thecaptive clinch nut of claim 60, wherein the outer surfaces of saiddisplacer and said shank are of reduced friction for providing bearingsurfaces of said nut against said sheet.
 89. The captive clinch nut ofclaim 60, wherein said first bearing surface is integral with said nutbody.
 90. The captive clinch nut of claim 60, wherein the displacer istapered inwardly.
 91. An assembly of parts including the captive nut ofclaim 60 and further including a sheet having an aperture formedtherein, the displacer and shank of said nut body being located withinsaid sheet and being coaxial with said aperture such that a ductiledeformed portion of said sheet lies within the undercut; and a spacebetween outside surfaces of said shank and an inside wall of said sheetaperture such that the nut is freely rotatable within said sheet whilebeing secured against substantial axial displacement therefrom, whereinthe combined lengths of said displacer and said shank are less than thethickness of said sheet such that said shank does not extend beyond aback side surface of said sheet.
 92. The assembly of parts of claim 91,wherein said nut is composed of a material having a hardnesssubstantially greater than said sheet.
 93. The assembly of parts ofclaim 92, wherein the portion of said sheet which lies within saidundercut area is received therein by the cold flow of metal of saidsheet.